The invention relates to belt installation tools and more particularly to a belt installation tool having an eccentric ramp surface whereby a flexible drive belt is stretched and progressively guided into a pulley groove.
Belt drive systems comprise a significant and widely used form of mechanical power transmission. Generally a belt runs between two or more pulleys, more particularly a driver and driven pulley.
In order to efficiently transmit power between the pulleys the belt is installed with a predetermined preload or tension. The amount of tension is generally a function of the horsepower and torque requirements of the drive. An increased horsepower or torque requirement will generally require a commensurate increase in the tension of the belt.
In order to achieve the proper tension, one or more of the pulleys is loosened so the shaft or shafts can be moved to allow a slack condition in the belt. Then, the belt is looped over the pulleys. The loosened pulley or pulleys are then pulled or tightened in a predetermined position, resulting in a tension in the belt. This process requires the pulley(s) to be mechanically adjusted to properly tension the belt.
Belts may be installed on pulley systems using other methods. For systems with an automatic tensioning device the tensioner is loaded, the belt is placed in an operating position, and the tensioner is released to its operational location. For systems without a tensioner, belts are wrapped around the pulleys and then a pulley is tightened to its final location by a bracket or similar devices.
Another method of installing a belt involves use of a tool that presses the belt into a pulley groove without the need for mechanically adjusting the pulleys. The tool is used adjacent to a pulley. It stretches the belt while laterally forcing it into a pulley groove.
Representative of the prior art is European Patent No. 0 831 247 B1 to Hutchinson which discloses a tool having a radial thrust area resting against a girth of the pulley, keeping a belt away from a pulley until it reaches a plane spaced from a pulley surface.
Also representative of the art is U.S. Pat. No. 4,193,310 (1980) to Boyer et al. which discloses a pulley having a diverging means extending radially and laterally from the rim for engaging and seating the belt on the pulley rim. This invention does not comprise a bearing surface for gradually entraining a belt on a pulley, instead having a peg that abruptly bends the belt into the pulley groove.
The prior art apparatus forces a belt to bend over small radius portions of the tool, causing high stress concentrations that damage the belt during installation. Further, high lateral loads damage the sidewalls of the belt. Finally, the transverse motion of the belt as it moves into the pulley groove may also damage the belt.
What is needed is a belt installation tool having an eccentric belt bearing surface having a variable radius and a portion of which substantially aligns with a pulley groove. What is needed is a belt installation tool having a hole for receiving a socket for engaging a pulley bolt. What is needed is a belt installation tool wherein the belt bearing surface has a radius substantially equal to a pulley radius. What is needed is a belt installation tool having a surface normal to the belt bearing surface for urging a belt into a pulley groove. The present invention meets these needs.
The primary aspect of the invention is to provide a belt installation tool having an eccentric belt bearing surface having a variable radius and a portion of which substantially aligns with a pulley groove.
Another aspect of the invention is to provide a belt installation tool having a hole for receiving a socket for engaging a pulley bolt.
Another aspect of the invention is to provide a belt installation tool wherein the belt bearing surface has a radius substantially equal to a pulley radius.
Another aspect of the invention is to provide belt installation tool having a surface normal to the belt bearing surface for urging a belt into a pulley groove.
Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.
The invention comprises a belt installation tool for installing a flexible belt on a pulley. The tool comprises an eccentric belt bearing surface. On one side, the radius of the tool is substantially equivalent to the radius measured from a pulley center to a pulley rim or flange. The bearing surface on this side of the tool stretches the belt and guides the belt into a pulley groove. To avoid damaging the belt the radius of the tool belt bearing surface and the pulley flange should be substantially equal over a substantial length of the tool. Centric to the tool radius a hole is provided to accommodate a single-end socket that projects through the tool to engage a crankshaft or pulley bolt, hence, the belt installation tool is centered to the pulley along the socket centerline. The tool and pulley are then turned with a ratchet attached to the socket. The belt is moved axially from the tool into the pulley grooves by a leaderblock, which is provided at the maximum tool radius on the belt bearing surface adjacent to the pulley grooves. By turning the tool about the crankshaft the leaderblock presses the belt flank causing it to move it into the pulley grooves. The leaderblock also comprises a lip to engage a pulley rim.